Probabilistic Performance Assessment of Fiber Optic Leak Detection Systems

Author(s):  
Alireda Aljaroudi ◽  
Faisal Khan ◽  
Ayhan Akinturk ◽  
Mahmoud Haddara

Leak detection systems (LDSs) play a major role in enhancing reliability and operability of oil and gas pipelines. They have the functional capabilities to detect, locate, and quantify leaks before they can cause devastating effects to the environment and operation. The performance of LDSs is typically influenced by three different types of failures that may have severe consequences: delayed detection, missed detection, and false detection of a leak. The consequences of these failures lead to extensive financial losses. For example, missed detection leads to oil spills and exposes operating companies to financial risk and destroyed image while false detection results in unnecessary deployment of personnel and equipment. To maintain safety of personnel and the environment and ensure operation continuity, LDSs should be assessed regularly. To fulfill this need, a probabilistic performance assessment scheme based on limit state approach for fiber optic LDS has been developed. The inherent uncertainties associated with leak detection and reporting capabilities are modeled to determine the LDS detection failure probability that combines two failure events: missed detection and delayed detection. Moreover, the probability of false detection is derived in terms of the lowest detectable change, the threshold. These three parameters establish the basis for an overall assessment scheme that can be used to predict the performance of the LDS. The proposed assessment scheme has been applied to a case study to demonstrate its usefulness and feasibility.

Author(s):  
Alireda Aljaroudi ◽  
Faisal Khan ◽  
Ayhan Akinturk ◽  
Mahmoud Haddara

Leak Detection Systems play a major role in enhancing reliability and operability of oil and gas pipelines. They have the functional capabilities to detect, locate and quantify leaks before they can cause drastic effects to environment and operation. The performance of Leak Detection Systems is typically affected by three different failures that have severe consequences, namely, delayed detection, missed detection and false detection of a leak. These failures pose a financial burden on operating companies. Missed detection leads to oil spill and exposes operating companies to financial risk and destroyed image while false detection results in unnecessary deployment of personnel and equipment. To insure operation continuity and maintain safe environment, Leak Detection Systems should be assessed at regular basis. To fulfill this need, a probabilistic performance assessment scheme based on limit state approach for Fiber Optic Leak Detection System (LDS) has been developed. The inherent uncertainties associated with leak detection and reporting capabilities are modeled to determine the LDS detection failure probability that combines two failure events, missed detection and delayed detection. Moreover, the probability of false detection is derived in terms of the lowest detectable change, the threshold. These three parameters establish the basis for an overall assessment scheme that can be used at any time to provide an up to date assessment about the Leak Detection System. The results will serve as the basis for deciding the actions that need to be taken to upgrade, repair or replace the system components or the system as a whole. The proposed assessment scheme has been applied to a case study to demonstrate its usefulness and feasibility.


Author(s):  
Alireda Aljaroudi ◽  
Faisal Khan ◽  
Ayhan Akinturk ◽  
Mahmoud Haddara ◽  
Premkumar Thodi

Insuring the integrity of subsea process component is one of the primary business objectives for oil and gas industry. One of the systems used to insure reliability of a pipeline, is the Leak Detection System (LDS). Different leak detection systems use different technologies for detecting and locating leaks that could result from pipelines. One technology in particular that is gaining wide acceptance by the industry is the optical leak detection systems. This technology has great potential for subsea pipelines applications. It is the most suited for underwater applications due to the ease of installation and reliable sensing capabilities. Having pipelines underwater in the deep sea present a greater challenge and a potential threat to the environment and operation. Thus, there is a need to have a reliable and effective system to provide the assurances that the monitored subsea pipeline is safe and functioning as per operating conditions. Two important performance parameters that are of concern to operators are the probability of detection and probability of false alarm. This article presents a probabilistic formulation of the probability of detection and probability of false detection for fiber optic LDS based systems.


2015 ◽  
Vol 15 (6) ◽  
pp. 873-882 ◽  
Author(s):  
Alireda Aljaroudi ◽  
Faisal Khan ◽  
Ayhan Akinturk ◽  
Mahmoud Haddara ◽  
Premkumar Thodi

Author(s):  
Chris Minto ◽  
Alastair Godfrey ◽  
Paul Clarkson ◽  
Alasdair Murray

Abstract External Leak Detection systems based on distributed fiber optic sensors (DFOS) offer the exciting potential to significantly reduce the overall amount of spilled product before a leak is detected and localized. Such systems are not well represented by industrial standards or recommended procedures and as a result most industrial attempts to validate the technology have been research-oriented and whilst these have contributed greatly to the knowledge base they have never been aimed at a full validation of the technology. Additionally, the lack of test facilities that can support the significant scale needed for validation (> 500 m straight line run) have led to a paucity of attempts to provide a baseline validation of such sensing technology leading to a lack of certainty over performance claims within the industrial user base and no robust method of testing such claims. With a significant customer base of deployed systems, OptaSense have developed a reproducible technology validation approach using full scale, full flow, representative leaks at the CTDUT test facility in Brazil. We have used these tests to validate 15 lpm leaks, detected and classified via their negative pressure pulse in ∼10 seconds and larger 150 lpm leaks, detected by our four modes of leak detection in ∼1 minute. Valid automated detection of a negative pressure pulse (NPP) was observed down to 1 mm holes in the pipe — representing a leak rate of only 1.5 lpm. The use of the NPP is shown to be a compelling rapid detection method. However, care is needed in testing since the use of a valve opening to stimulate a pulse is shown to be significantly inferior to burst disks due to the increased valve-opening time giving rise to a reduced amplitude pressure pulse. The conventional external leak detection signals of Orifice Noise, Ground Strain and Temperature Change can all be shown to be replicated at the large-scale test facility by these means leading to the potential to establish a valid Probability of Detection for all approaches. With validation now possible, client verification on site has also been addressed with a two-step approach being developed that replicates the validation approach detailed above. Negative Pressure Pulses are used for stand-alone leak detection and can be safely stimulated via accessible valve sites and product release via a burst disc / valve and orifice combination. To stimulate the Multiple Mode behavior (excluding Negative Pressure Pulse) a controlled fluid release injection mechanism has been developed, which can be introduced at an appropriate offset from the pipeline (mirrored from fiber offset) at any desired location with the minimum of preparation. Ground probe deployment techniques have been designed to simulate a leak event at the appropriate location resulting in the similar external signals arising on the fiber. This paper presents the benefits of large-scale validation approaches to performance bound acoustic-based leak detection systems and presents established options for in-field verification on customer owned systems.


2014 ◽  
Vol 699 ◽  
pp. 891-896 ◽  
Author(s):  
Mohamad Fani Sulaima ◽  
F. Abdullah ◽  
Wan Mohd Bukhari ◽  
Fara Ashikin Ali ◽  
M.N.M. Nasir ◽  
...  

Pipelines leaks normally begin at poor joints, corrosions and cracks, and slowly progress to a major leakage. Accidents, terror, sabotage, or theft are some of human factor of pipeline leak. The primary purpose of Pipeline leak detection systems (PLDS) is to assist pipeline operators in detecting and locating leaks earlier. PLDS systems provide an alarm and display other related data to the pipeline operators for their decision-making. It is also beneficial because PLDS can enhance their productivity by reduced downtime and inspection time. PLDS can be divided into internally based or computational modeling PLDS Systems and external hardware based PLDS. The purpose of this paper is to study the various types of leak detection systems based on internally systemtodefine a set of key criteria for evaluating the characteristics of this system and provide an evaluation method of leak detection technology as a guideline of choosing the appropriate system.


2020 ◽  
Vol 75 ◽  
pp. 101772
Author(s):  
Mahmoud Meribout ◽  
Lyes Khezzar ◽  
Abdelwahid Azzi ◽  
Nabil Ghendour

2021 ◽  
Author(s):  
Cindy Chairunissa ◽  
Deny Kalfarosi Amanu ◽  
Grizki Astari ◽  
Eska Indrayana

Abstract Kedung Keris (KK) is a sour oil field based in Cepu Block, Indonesia. KK field was originally planned to have a processing facility with separate pipelines to deliver crude & produced water, while the gas was planned to be flared. To reduce cost, this concept was changed to a wellpad with full well stream pipeline with new technology of Fiber Optic Leak Detection Sensing System (LDSS) as a key enabler. The fiber optic LDSS functions by leveraging fiber optic cable attached to the pipeline to detect leak as well as intrusion to the pipeline's Right-of-Way through real-time analysis of physical characteristics of a leak and intrusion, such as changes in temperature, pressure, ground strain and acoustics. The implementation of LDSS, together with other safeguards built into the pipeline design, operations and maintenance, allowed the KK Project to eliminate the separation facility at KK wellpad and an additional water pipeline. It also reduces the flaring by billions of standard cubic feet of gas cumulative until end of PSC life as originally all gas planned to be flared. The change of KK Project concept altogether yielded tens of millions of US dollar gross cost savings (~30% of CAPEX + OPEX reduction) following the KK startup in late 2019. The installed LDSS proven to detect leak for up to few meters location accuracy and has intrusion detection capability. KK Project has pioneered the implementation of fiber optic leak detection system for Indonesia oil and gas companies. This work provided further insight to the utilization of such technology in full well stream pipeline where traditional leak detection system implementation will not be acceptable. Consecutively, full well stream pipeline deployment can lead to future CAPEX + OPEX efficiency in facility project design and operation, as well as flaring reduction opportunity.


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